Retractable belt pulley system



Dec. 30, 1969 a BENTON ETAL 3,486,606

RETRACTABLE BELT PULLEY SYSTEM Filed April 10, 1967 INVENTORS DEN TO/V E /c pig/mm F SESS/MiHAl/S -Liz; 7. k I

Arm/WES United States Patent 3,486,606 RETRACTABLE BELT PULLEY SYSTEM Eric B. Denton, Seattle, and Desmond F. Sessinghaus, Tacoma, Wash., assignors to Weyerhaeuser Company, Tacoma, Wash., a corporation of Washington Filed Apr. 10, 1967, Ser. No. 629,783 Int. Cl. B65g /16 US. Cl. 198-165 2 Claims ABSTRACT OF THE DISCLOSURE A belt supporting pulley system wherein the belts are held in tension by multiple pulleys. In the normal operating position the belts are held .by the pulleys so that they pass close to the surface of a turn-around drum to hold materials against the surface as the direction that the materials are conveyed is reversed. In the released position at least two of the pulleys are moved relative to the drum, providing access to the conveying space between the belts and drum but without slacking the tension on the belts.

CROSS REFERENCE TO RELATED APPLICATIONS This application relates to a belt pulley system useful in the apparatus disclosed in the US. patent application entitled Reverse Pass In-Line Veneer Production System, Attorney Docket No, 4068, filed Mar. 27, 1967, in the name of Conant Dodge, having a common assignee with the instant application.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to an improved belt and pulley system and in particular to an apparatus permitting a change in the path of the belt without slacking belt tension.

Description of prior art Turn-around conveying units which reverse the direction of the material being conveyed are well known. The dryer disclosed in the US. Patent No. 1,511,400 to Daly utilizes rolls 7, 8, 9 and 10 to reverse the direction that the strips of veneer are conveyed. It should be noted that the material conveyed around these rolls is held between endless belts 14 and 15. If a piece of material becomes jammed or dislocated as it reverses direction, there is no easy way to remove or reposition it.

SUMMARY OF THE INVENTION Applicants have developed a system of pulley supports wherein some or all of the pulleys can be moved relative to the turn-around drum so that the path of the belts supported by the pulleys can be moved away from the drum surface. This provides access space so that the material between the drum surface and the belts can be removed or repositioned. It has been found that simply reducing the tension on the belts permits some case in removing or repositioning the material, but often such slacking causes the belts to fall off of some of the pulleys. This requires additional downtime while the belts are repositioned. Applicants have therefore developed-a pulley system which provides the access space needed for material adjustment while at the same time retains the belts in tension.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a side elevation view of the general arrangement of the turn-around mechanism utilizing the retractable belt pulley system of the instant invention;

FIGURE 2 is a side elevation view of the retractable belt pulley system shown in FIGURE 1 with some parts 3,486,606 Patented Dec. 30, 1969 removed, showing a change in the path of the belt; and

FIGURE 3 is an enlarged section view with some parts broken away for clarity as seen through line 3-3 of FIGURE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in more detail, FIGURE 1 shows the general arrangement of turn-around mechanism 65, such as that utilized in the reverse pass dryer disclosed in the above referred to patent application to Conant Dodge. The general arrangement of the retractable pulley system includes turn-around drum means 58, flexible hold-down belts 66 which are trained about and supported by pulleys 67, 68 and 69, These pullleys may be in the form of drums or individual pulleys 68a to 6821, etc., but in any case they rotate about axes parallel to the axis of the turn-around drum 58.

In the environment shown, material, such as veneer 49, exists from a first work station, such as drying chamber 50, being held between upper hold-down cables 52, which are supported by pulley 54, and upper carrying cables 56, which are supported by turn-around drum 58. As the turn-around drum 58 rotates, the veneer 49 is held against and travels with the surface of the turn-around drum 58 by means of hold-down belts 66, as shownin their first or normal position in FIGURE 1. As the veneer 49 completes its change of direction, it is conveyed onto lower carrying cables 60, which are supported by pulleys 62. The veneer is held down against cable 60 by the lower hold-down cables 56, which are also the upper carrying cables.

The tension in the flexible belts 66 is maintained by the positioning of pulleys 67, 68 and 69 relative to one another. As shown, pulley 69 is supported by a first mounting means 73, which is connected through piston rod 72 to a suitable positioning means, such as expandable motor 71. The mounting means 73 is guided in its movement along guide track 74, which is suitably supported on frame means including horizontal frame member 75 and leg member 76. Pulley 68 is rotatably mounted and supported by second mounting means 78, as it rotates about pulley shaft 79. In one installation of this system several belts 66a to 66n are supported by a number of pulleys 67a to 67n, 68a to 68m and 69a to 6%. All of the pulleys 67a to 67n are rotatably supported on one shaft. In a similar manner the pulleys 68a to 68n are rotatably supported on shaft 79. While one shaft and one positioning means could be used to support pulleys 69a to 69n, better tensioning results when each pulley 69 is separately supported and positioned.

Second mounting means 78 is movable along horizontal rail 84 through the operation of a pinion crank 80, which is keyed to pinion gear shaft 81, which supports pinion gear as'it engages rack 83, as shown in FIGURE 3. In FIGURE 1 pulley 68 is in its normal position for establishing a path for flexible belt 66, which in turn establishes one boundry of a conveying path for the material, such as veneer 49, with the other boundry established by the surface of the turn-around drum 58. If individual pieces of veneer 49 become dislodged or overlapped, it is possible to retract the piston rod 72 and the motor 71 to move the pulley 69 to the position shown in FIGURE 2 while, at the same time maintaining the tension on the flexible belt 66 by moving the second mounting means 78 through the action of the pinion gear 85 and rack 83 along horizontal rail 84 to the position shown in FIGURE 2. In this way, there is provided easy access to the surface of the turn-around drum 58 for removing or repositioning the material.

If more exposure of the surface of the turn-around drum 58 is necessary, the rail 84 could be extended and the leg 76 could be relocated so that the pulley 68 could be moved further away from the turn-around drum 58. Another alternative of structure which would provide the same results in maintaining the tension on the flexible belt 66 while at the same time providing access to the surface of the turn-around drum 58 would be to mount the supports of pulleys 67 and 68 onto one frame member which can move relative to the turn-around drum 58 as the pulley 69 is moved away from the drum 58. If tension is not maintained on the flexible belt 66 when two or more of the pulleys, such as 68 and 69, are moved away from the turn-around drum 58, the belts 66 have a tendency to fall olf of their pulley runs and this requires careful repositioning when the tension is restored in its nomral operating position, as shown in FIGURE 1.

It is therefore seen that We have disclosed a generally improved pulley and flexible belt system which is retractable away from its conveying position in such a manner that the tension on the flexible belt is maintained.

What is claimed is:

1. A retractable belt pulley system including:

drum means, pulley means, flexible belt means, transport means, mounting means, and positioning means in combination;

said drum means rotatably mounted about a first axis and including an exterior surface;

said transport means trained around said drum;

said pulley means rotatably mounted about axes generally parallel to said first axis;

said belt means trained about and supported by said pulley means;

said pulley and drum means spaced in a first position relative to one another so that said belt means, when held in tension, establishes one boundary of a conveying path around a portion of said drum with a second boundary defined by a portion of said transport means:

first mounting means supporting one of said pulley means;

second mounting means supporting a second of said pulley means;

positioning means operatively connected to said first and said second mounting means to change the positions of said first and second pulley means relative to said drum means from said first position to a second position wherein said belt means is retained in tension but is at least partially displaced from said transport means to permit access to a portion of said conveying path.

2. The apparatus of claim 1 wherein:

said positioning means includes a retractable motor means operatively connected to said first mounting means and a rack-and-pinion drive operatively connected to said second mounting means.

References Cited UNITED STATES PATENTS 1,347,121 7/1920 Rice 198-208 2,605,883 8/1952 Thames 198167 3,238,802 3/1966 Budzyn 74-219 3,356,207 12/1967 Hansel 198165 RICHARD E. AEGERTER, Primary Examiner US. Cl. X.-R. 74219; 198208 

